Article 338

[bradleymattlin]

I have a question on article 338.10 b (4). It says where installed in thermal insulation you have to use the 60 degree column. Can anyone explain what thermal insulation is. By reading this, it says now number 2 alumium ser is only good for 75 amps. Might be wrong how iam reading it but wanted some opinions.

 

[augie47]

As far as I know it references your standard rolled/blown/etc insulation for attics, walls, floors....

 

[bradleymattlin]

So number 2 alumium ser ran inside to subpanels in house isnt good for 90 amps any more buy what that code article says.

 

[Gregg Harris]

So number 2 alumium ser ran inside to subpanels in house isnt good for 90 amps any more buy what that code article says.

When it is surounded or imbeded in thermal insulation. There is no distinction as to what type or how much insulation or lenght of cover by the insulation. If it can be brought into the structure or run in the structure where it is not in contact with the insulation then it would not apply.

 

[kbsparky]

So number 2 alumium ser ran inside to subpanels in house isnt good for 90 amps any more buy what that code article says.

That's correct if it's buried in insulation. Keep it clear from any insulation, and you may be able to use your higher ratings.

Unless it's the main feeder for the whole house. Then it's rated for 100 Amps.

 

[bradleymattlin]

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Thanks everybody for the input it helped out alot.